In such tool assemblies, particularly of the rotary kind, the two component members of the assembly are wedge-coupled together as a result of the torque generated during rotary machining operations. For this purpose, the component members of the assembly can be respectively formed with similarly shaped projections and recesses which are adapted to cooperate with each other so as to bring the component members into a clamping engagement. The coupling between the component members of the assembly has to be rigid enough to meet the reliability requirements, especially for hard machining conditions, as well as to provide accurate mutual coaxial alignment of the component members, with respect to each other and with respect to the central rotary axis and also to ensure absence of rotational clearance when rotary motion is transferred from a driving component member to a driven component member.
There are known tool assemblies such as are used in composite milling cutters, where the coupling of a replaceable front end or intermediate component to a basic holder is achieved by means of pins which protrude from the component to engage with corresponding recesses in the basic holder.
These assemblies are disadvantageous in view of the fact that to ensure reliable coupling many additional constructional elements are required.
In another known assembly disclosed in U.S. Pat. Nos. 4,834,597 and 4,934,883 and used with milling cutters and drilling tools, there are two component members, one of which is a tool or an adapter for a tool and the other is a holder having a recess adapted to receive a correspondingly-shaped projection of the first member. The cooperating surfaces of the recess and the projection have a non-circular cross-section with at least two radial extensions so that the component members of the assembly cannot rotate with respect to one another. The assembly further comprises means for relative clamping together of the members.
The disadvantage of this known assembly is that the actual regions of contact between the cooperating surfaces of the component members and therefore the distribution of the wedging forces generated during machining operations cannot be exactly predetermined as the contact between cooperating surfaces may take place anywhere along their peripheries. Thus, in order to provide a rigid coupling between the component members, an extended region of contact between to component members is needed. In consequence, and in order to ensure a maximum transference of torque, the projection must be so designed as to extend around the entire periphery of the driven member. Furthermore, the use of such an extended projection is very disadvantageous with rotary milling cutters in which are formed flutes, seeing that the presence of such flutes essentially limits the space available in which the projection can be accommodated.
It is an object of the present invention to provide a multi-component tool assembly, in which the above-referred-to disadvantages are substantially reduced or overcome.